Recently the Department of Energy (DOE) has introduced the Compressed Air Challenge, a nation wide program to reduce the amount of energy used by plants using compressed air. Specifically, the DOE issued the following press release in January 1998:
DOE LAUNCHES xe2x80x9cCOMPRESSED AIR CHALLENGE.xe2x80x9d
The US Department of Energy (DOE) has announced a new program designed to reduce US industry""s electricity costs $150 million per year by helping manufacturers improve the efficiency of compressed air systems, which are considered industry""s xe2x80x9cfourth utilityxe2x80x9d after electricity, gas, and water. Compressed air systems use $1.5 billion per year in electricityxe2x80x94equal to Connecticut""s overall electricity consumption or 1 percent of total US generation. The first-year goal of 10 percent improvement in efficiency would mean greenhouse gas emission reductions of about 700,000 tons of carbon per year by 2010, equivalent to removing 130,000 cars from the road. Compressed air system improvements can be achieved simply by eliminating air supply leaks, lowering air supply pressures, and properly maintaining components, supply lines, and filters. (DOE press release, January 1998)
Much expensive compressed air is wasted because of leaking air valves on compressed air systems. Just one drain valve leaking compressed air can cost a factory $1,000 per month. When this loss is multiplied by many leaking valves, the cost is a severe drain on a company""s capital.
Further, the air valve replacement cost is expensive from a labor point of view because many plumbing fittings conventionally must be disassembled and reassembled. It is not uncommon for six to ten fittings to be involved in replacing a solenoid drain valve from an air compression tank.
The principal other problems associated with solenoid drain valves are as follows:
1. All valves need to have a strainer placed in an upstream position with respect to the valve to filter out dirt that could otherwise get underneath the seat and allow the valve to stick open wasting air.
2. Most external strainers that are used with valves allow for debris to escape and enter into the valves they are supposed to be protecting when they are opened to clean out the filter screen.
3. Most valves are harder to install very near the vessel that they are draining due to the swing radius of the valve about a central longitudinal axis. Extra parts or unions have to be supplied to make the installation in many applications.
4. Due to the fact that most air valves tend to plug, people normally set the time cycle for purging moisture from the lines to be on for more than is needed. This leads to much wasted air.
5. When current valves are installed on receiver tanks the manual drain that was in the bottom of the tank has to be replaced for code purposes, before the valve is installed, and this requires more fittings.
It is therefore a principal object of the invention to provide a solenoid drain valve where the valve member itself, usually a ball valve, and the screening element are both located in the valve body.
A further object of this invention is to provide a solenoid drain valve that is self cleaning.
A still further object of this invention is to provide a solenoid drain valve that can be replaced with a minimum number of plumbing fittings.
A still further object of this invention is to provide a solenoid drain valve as that can be cleaned without being disassembled.
These and other objects will be apparent to those skilled in the art.
A one piece air valve body incorporates a built in strainer and a ball valve which can be used for cleaning out the strainer without any disassembly. Also the orifice to the valve is mounted on top of the strainer so gravity will help in keeping any debris that might get through the filter screen from entering and causing the valve to fail. The design of the inlet is such that a chamfer is machined on the inside so a standard female swivel fitting can be installed without adding a separate union. This valve body design can work for both direct acting or diaphragm operated valves.
A solenoid connected to a timer periodically is energized to open the valve to open the valve and purge moisture collected in the system.